The identification of clinical indicators with good predictive ability allows the nurse to minimize the existing variability in clinical situations presented by the patient and to accurately identify the nursing diagnosis, which represents the true clinical condition. The purpose of this study was to analyze the accuracy of NANDA-I clinical indicators of the nursing diagnosis ineffective airway clearance (IAC) in children with acute respiratory infection. This was a prospective cohort study conducted with a group of 136 children and followed for a period of time ranging from 6 to 10 consecutive days. For data analysis, the measures of accuracy were calculated for clinical indicators, which presented statistical significance in a generalized estimated equation model. IAC was present in 91.9% of children in the first assessment. Adventitious breath sounds presented the best measure of accuracy. Ineffective cough presented a high value of sensitivity. Changes in respiratory rate, wide-eyed, diminished breath sounds, and difficulty vocalizing presented high positive predictive values. In conclusion, adventitious breath sounds showed the best predictive ability to diagnose IAC in children with respiratory acute infection.